A stereotaxic atlas of the brainstem forMacaca mulatta in the sitting position

Attempts to use existing stereotaxic atlases of the lower brainstem of monkeys for the placement of microelectrodes in the cranial nerve nuclei of awake animals have met with little success. The relationship of these nuclei to the bony structures used for orienting the head are probably altered when the position of the body is radically changed from the horizontal to the vertical (sitting) position. The atlas presented is based upon Macaca mulatta monkeys sitting in position in a primate restraint chair. This standard orientation provides a necessary frame of reference for accurate localization of lower brainstem structures.